Oxygen Isotopes

This paper examines the potential of oxygen stable isotope composition of Sparidae (sea-bream) tooth
enamel phosphate (d18OP) as an indicator of the habitat in which the fish were captured. The isotopic
compositions of Sparidae molariform teeth recovered from the coastal site of Tel Dor (northern coast of
Israel), from a sequence dated to the 12the7th centuries BCE and from modern samples were studied.
The d18OP values of the archaeological specimens exhibited a wide range of values, varying between 21.3
and 25.2 ± 0.2‰.
While d18OP values from the teeth dated to the 12the9th centuries BCE resembled typical East
Mediterranean coastal water, some of the later teeth, dated to the 9the7th centuries BCE, exhibited
higher values. The later values indicate tooth enamel deposition in a hyper-saline environment similar to
d18OP values of Sparidae observed at Bardawil Lagoon (Southeastern Mediterranean coast, east of the
Suez Canal, Egypt). Prior to this study all Sparidae fish recovered at Tel Dor were regarded as evidence of
local fishing activity. The current results exhibit, for the first time, that some of the Sparids may have
been exported from the Bardawil Lagoon. We discuss, however, an alternative scenario, namely, the
possible existence of saline lagoons near Tel Dor in antiquity.

Determining the diet of an extinct species is paramount in any attempt to reconstruct its paleoecology. Because the distribution and mechanical properties of food items may impact postcranial, cranial, mandibular, and dental morphologies related to their procurement, ingestion, and mastication, these anatomical attributes have been studied intensively. However, while mechanical environments influence skeletal and dental features, it is not clear to what extent they dictate particular morphologies. Although biomechanical explanations have been widely applied to extinct hominins in attempts to retrodict dietary proclivities, morphology may say as much about what they were capable of eating, and perhaps more about phylogenetic history, than about the nature of the diet. Anatomical attributes may establish boundary limits, but direct evidence left by the foods that were actually (rather than hypothetically) consumed is required to reconstruct diet. Dental microwear and the stable light isotope chemistry of tooth enamel provide such evidence, and are especially powerful when used in tandem. We review the foundations for microwear and biogeochemistry in diet reconstruction, and discuss this evidence for six early hominin species (Ardipithecus ramidus, Australopithecus anamensis, Au. afarensis, Au. africanus, Paranthropus robustus, and P. boisei). The dietary signals derived from microwear and isotope chemistry are sometimes at odds with inferences from biomechanical approaches, a potentially disquieting conundrum that is particularly evident for several species. Am J Phys Anthropol 148:285–317, 2012. © 2012 Wiley Periodicals, Inc.

The major states, in which Earth's climate operates, i.e., icehouse, greenhouse and hothouse, are epochs of tens of
millions of years. These states set long-termboundary conditions that need to be considered for climate and sea level interpretations. This paper summarizes the conceptual models for hydrological cycling derived from the characteristics of these three climate states. While glacio-eustatic forcing of sea-level changes under icehouse climate conditions is fairly well understood, the drivers of eustatic sea-level fluctuations under greenhouse conditions remain enigmatic. This lack of understanding may be related to incoherencies in the current ideas about the impact of accelerated hydrological cycling on sea level under greenhouse climate conditions.
As an example for a greenhouse climate, we review evidences that link proxies for climate and sea level for the intensely studied, but controversially discussed, mid-Cretaceous  sea-level history. Based on sequence stratigraphy and a recently published high-precision timescale, we demonstrate that the late Middle Turonian Pewsey δ13C isotope maximum represents a major transgression, not a regression as previously stated, which conflicts with the interpretation of a co-occurring δ18O maximum to reflect a short glacial episode. This contradiction can be solved by the concept, presented here, that dominance of aquifer-eustasy characterized sea-level forcing during the Turonian greenhouse climate, despite a possible, though contentious, sporadic presence of minor ice sheets. The effects of temperature and ice volume both lead to a pronounced δ18Ocarb maximum during glacio-eustatic regressions. In contrast, the opposing effects of temperature and groundwater volume on oxygen-isotope fractionation lead to a δ18Ocarb maximum during aquifer-eustatic transgressions. We suggest that, throughout Earth history, both aquifer-eustatic and glacio-eustatic forcing formed a combined sea-level response, with dominance of aquifer-eustasy being typical for the greenhouse climate mode. During the icehouse mode, aquifer-eustasy apparently remains active as a background process, but is outpaced by the glacio-eustatic effect.

The use of saliva sampling for the measurement of total body water by H2 18O stable isotope dilution was assessed. The H2 18O abundance in saliva reached a constant value by three hours after isotope administration, and the total body water calculated from the 3-h saliva values was not significantly different from the value calculated from the 4- and 6-h serum samples. The results indicated that isotopic equilibration between these fluids was rapid and complete. Comparison of total body water calculated from the paired serum and saliva studies indicated that the relative precision of the determination was between 0.8 and 1.5%. Saliva sampling is noninvasive and is well suited for use in children in field studies.

A suite of 30 eclogite and pyroxenite xenoliths recovered from the Jurassic Victor kimberlite in the western Superior Province are investigated to determine their formation and emplacement in the sub-continental lithospheric mantle (SCLM). The samples have a wide compositional range, including low-Mg and high-Mg varieties. The low-Mg eclogites have a shallow origin as plagioclase-bearing protoliths that were subsequently subducted and emplaced into the SCLM. This is supported by their generally flat MREE to HREE compositions, the presence of kyanite and a positive Eu anomaly in the kyanite-bearing sample, as well as d18O in three low-Mg eclogites that are higher than the pristine mantle value. LREE depletion in the low-Mg eclogites, along with unradiogenic 87Sr/86Sr indicate that they were not affected by widespread metasomatism after emplacement in the SCLM. The high-Mg eclogites and pyroxenites have compositional characteristics that require a distinct origin to the low-Mg eclogites. Their bulk compositions, LREE-enriched trace element patterns and in particular, occurrence of unradiogenic 187Os/188Os in pyroxenite, is consistent with formation by reaction of broadly siliceous melts (generated from the melting of low-Mg eclogites) with depleted peridotite. A subduction origin of the eclogites studied here is consistent with seismic and field-based studies that have reported terrane accretion by successive subduction of the west–east orientated terranes in the western Superior Province. Although the timing of eclogite and pyroxenite formation could not be constrained, radiogenic 187Os/188Os require long-term isolation from the convecting mantle and supports a Neorchaean age for their formation.

The Earth’s climate is changing.  When humankind emerged from the last major Ice Age, about 21,000 years ago, both poles and much of the northern continents were covered with expanding ice sheets (Figure 1).  In the past 10,000 years the Earth  has naturally warmed and the ice sheet have retreated towards the poles.  However, make no mistake about it, we are still locked in the depths of an Icehouse world.
According to a natural cycle, controlled in part, by changes in the shape of the Earth’s orbit, this warm period should continue for another 40,000 years or so. Then, if Nature has its way, the Earth will slip back again into the grips of another major Ice Age and frigid landscapes will once again expand outward from the poles.
But Nature may not have its way.  Things have changed.  We have changed things. The addition of CO2 to the atmosphere during the last 200 years of human industry has amplified this natural warming trend and the average global temperature has risen rapidly. The average global temperature was 12 ˚ C during the Last Glacial Maximum (21,000 years ago).  During the following Interglacial period, the average global temperature slowly rose to 13.8˚C.  Since 1880, it has increased another .6˚ degrees to 14.4˚C ( as of 2015).  This rate of warming is 30 times faster1 than what occurred during the previous 20,000 years.
How much more will global temperatures rise?  Will the increase in global temperature be enough to push the Earth from a frigid Icehouse world with thick polar icecaps to a sweltering Hothouse world with palm trees and alligators living at the North Pole?  This is the question that I would like to address in this essay.
But before we discuss how much the Earth will warm, there are a few other questions we must tackle, such as:
-What exactly is an Icehouse World, and what causes the Earth to cool off so dramatically? ,
-Conversely, what is a Hothouse World?, and what  causes the Earth to heat up so dramatically?
-And, what do we mean by “the average global temperature”?  How is it calculated?

Objectives: The Early Bronze Age (EBA; ca. 3,600-2000 BCE) of the southern Levant underwent considerable transformation as agro-pastoral communities began to utilize their land more intensively, constructing larger, fortified towns prior to site abandon-ment at the end of the third millennium. At the site of Bab adh-Dhra' in Jordan, the dead of the Early Bronze (EB) II-III (ca. 3,100-2,500 BCE) period were communally interred within charnel houses, but important disparities between these structures and their contents may be reflective of ownership and use by particular extended kin groups whose activity patterns, subsistence strategies, and even social status may have differed from one another. Subsequently, we hypothesized that differences in mobility and dietary intake may differentiate tomb groups from one another. Materials and Methods: Dental enamel from 31 individuals interred in three different Early Bronze Age charnel houses (A56, A22, A55) at Bab adh-Dhra', Jordan were analyzed for strontium, oxygen, and carbon isotope values. Results: Strontium isotope ratios (range: 0.70793-0.70842) possessed medians that did not differ statistically from one another, but had ranges that exhibited significant differences in variance. Carbon isotope values (x= −13.2 ± 0.5‰, 1σ) were not significantly different. Discussion: General similarities in human isotopic signatures between EB II-III char-nel houses A22 and A55 suggest that their activities were likely similar to one another and agree with findings from excavated domestic spaces with little archaeological evidence for economic, social, or political differentiation. More variable strontium isotope ratios and lower carbon isotope values from A22 could reflect a greater involvement with pastoralist practices or regional trade, including the consumption of more 13 C-depleted foods, while those in A55 may have led a more sedentary lifestyle with greater involvement in cultivating orchard crops. All charnel houses contained nonlocal individuals likely originating from other Dead Sea Plain sites with no EB II-III cemeteries of their own, supporting the idea that extended kin groups throughout the region returned to Bab adh-Dhra' to bury their dead. K E Y W O R D S Bronze Age, carbon isotopes, Near East, oxygen isotopes, residential mobility, social identity, strontium isotopes, subsistence

This study provides a comprehensive and quantitative estimate of how global temperatures have changed during the last 540 million years. It combines paleotemperature measurements determined from oxygen isotopes with broader insights obtained from the changing distribution of lithologic indicators of climate, such as coals, evaporites, calcretes, reefs, and bauxite deposits. The waxing and waning of the Earth’s great polar icecaps have been mapped using the past distribution of tillites, dropstones, and glendonites. The global temperature model presented here includes estimates of global average temperate (GAT), changing tropical temperatures (∆T◦ tropical), deep ocean temperatures, and polar temperatures. Though similar, in many respects, to the temper- ature history deduced directly from the study of oxygen isotopes, our model does not predict the extreme high temperatures for the Early Paleozoic required by isotopic investigations. The history of global changes in tem- perature during the Phanerozoic has been summarized in a “paleotemperature timescale” that subdivides the many past climatic events into 8 major climate modes; each climate mode is made up of 3-4 pairs of warming and cooling episodes (chronotemps). A detailed narrative describes how these past temperature events have been affected by geological processes such as the eruption of Large Igneous Provinces (LIPS) (warming) and bolide impacts (cooling). The paleotemperature model presented here allows for a deeper understanding of the inter- connected geologic, tectonic, paleoclimatic, paleoceanographic, and evolutionary events that have shaped our planet, and we make explicit predictions about the Earth’s past temperature that can be tested and evaluated. By quantitatively describing the pattern of paleotemperature change through time, we may be able to gain important insights into the history of the Earth System and the fundamental causes of climate change on geological timescales. These insights can help us better understand the problems and challenges that we face as a result of Future Global Warming.

A 13-million-year continuous record of Oligocene climate from the equatorial Pacific reveals a pronounced “heartbeat” in the global carbon cycle and periodicity of glaciations. This heartbeat consists of 405,000-, 127,000-, and 96,000-year eccentricity cycles and 1.2-million-year obliquity cycles in periodically recurring glacial and carbon cycle events. That climate system response to intricate orbital variations suggests a fundamental interaction of the carbon cycle, solar forcing, and glacial events. Box modeling shows that the interaction of the carbon cycle and solar forcing modulates deep ocean acidity as well as the production and burial of global biomass. The pronounced 405,000-year eccentricity cycle is amplified by the long residence time of carbon in the oceans.

Following previous studies on counterfeit of wines with synthetic ingredients, the possibility of frauds by natural external L-tartaric acid has also been investigated. The aim of this research was to map the stable isotope ratios of L-tartaric acid coming from botanical species containing large amounts of this compound: grape and tamarind. Samples of L-tartaric acid were extracted from the pulp of tamarind fruits originating from several countries and from grape must. δ13C and δ18O were measured for all samples. Additional δ2H measurements were performed as a complementary analysis to help discrimination of the botanical origin. Different isotopic patterns were observed for the different botanical origins. The multivariate statistical analysis of the data shows clear discrimination among the different botanical and synthetic sources. This approach could be a complementary tool for the control of L-tartaric acid used in oenology. Copyright © 2007 John Wiley & Sons, Ltd.

ABSTRACT: Analysis of stable carbon and nitrogen isotopes from soft or mineralized tissues is a direct and widely used
technique for modeling diets. In addition to its continued role in paleodiet analysis, stable isotope analysis is now
contributing to studies of physiology, disease, and nutrition in archaeological and living human populations. In humans
and other animals, dietary uptake and distribution of carbon and nitrogen among mineralized and soft tissue is carried
out with varying efficiency due to factors of internal biology. Human pathophysiologies may lead to pathology-influenced
isotopic fractionation that can be exploited to understand not just skeletal health and diet, but physiological
health and nutrition. This study reviews examples from human biology, non-human animal ecology, biomedicine, and
bioarchaeology demonstrating how stable isotope analyses are usefully applied to the study of physiological adaptation
and adaptability. Suggestions are made for future directions in applying stable isotope analysis to the study of nutritional
stress, disease, and growth and development in living and past human populations.

Crustal recycling patterns during the evolution of the Neoproterozoic Arabian-Nubian Shield (ANS) were defined using the oxygen isotope ratio of zircon [δ18O(Zrn)]. Evidence for early (~ 870–740 Ma) crustal recycling in the northernmost ANS (southern Israel and Sinai, Egypt) is given by laser fluorination analysis of bulk zircon separates, which yield higher than mantle δ18O(Zrn) values of several island arc complex (IAC) orthogneisses (6.9 to 8.2‰) and also from the average δ18O(Zrn) value of 6.4‰ determined for detrital zircons (~ 870–780 Ma) from the Elat-schist; the latter representing the oldest known rock sources in the region. These results indicate prolonged availability of surface-derived rocks for burial or subduction, melting, and assimilation at the very early stages of island arc formation in the ANS. Other IAC intrusions of ~ 800 Ma show mantle-like δ18O(Zrn) values, implying that not all magmas involved supracrustal contribution. Much younger (650–625 Ma) deformed syn-collisional calc-alkaline (CA1) intrusions are characterized by δ18O(Zrn) values of 5.0 to 7.9‰ indicating continued recycling of the felsic crust.The main sample set of this study comprises rocks from the mostly granitic, post-collisional calc-alkaline (CA2: ~ 635–590 Ma) and alkaline (AL: ~ 608–580 Ma) magmatic suites. Despite having distinct geochemical characteristics and petrogenetic paths and spans of magmatic activity, the two suites are indistinguishable by their average δ18O(Zrn) values of 5.7 and 5.8‰ pointing to the dominance of mantle-like δ18O sources in their formation. Nonetheless, grouping the two suites together reveals geographical zoning in δ18O(Zrn) where a large southeastern region of δ18O(Zrn) = 4.5 to 5.9‰ is separated from a northwestern belt with δ18O(Zrn) = 6 to 8‰ by a ‘6‰ line’.It is thus suggested that all CA2 and AL magmas of the northernmost ANS were derived from mantle-like δ18O reservoirs in the mafic lower-crust and the lithospheric-mantle, respectively. However, while in the northwestern belt these magmas intruded a thick crustal section and assimilated ~ 15–35%, high-δ18O IAC+CA1 material, magmas in the southeastern region intruded a thinner crust and little or no contamination occurred. The proposed NW–SE variance in crustal thickness during the late Neoproterozoic fits well with the geometry of the fan shaped rifting model proposed by Stern [Stern, R.J., 1985. The Najd Fault System, Saudi Arabia and Egypt: a late Precambrian rift related transform system. Tectonics 4, 497–511.] for this region. Deep parts of the lithosphere were beginning to rift at ~ 630 Ma, allowing the asthenospheric mantle to rise and transfer heat to the lithosphere. This resulted in vast melting of the mafic lower-crust to produce the batholithic CA2 magmas. Later (~ 610 Ma) percolation of lithospheric-mantle melts (possibly along deep seated lithospheric-scale faults) introduced AL magmas to shallow levels of the crust. Intrusion of CA2 and AL mantle-like δ18O parent magmas into the thinned southeastern crust did not involve assimilation of older crust whereas similar intrusion into the thicker northwestern crust resulted in mild assimilation of high-δ18O pre-635 Ma crust.An important implication from our results is that petrogenesis of some high-δ18O AL magmas of the northernmost ANS involved assimilation of supracrustal material. Felsic intrusions of the AL suite were previously described as A-type granites derived solely from mantle melts with no crustal components. Our results contribute to the “A-type petrogenesis debate” by showing that their formation can involve recycling of crustal material.

The carnivores from Trinchera Dolina level 6 (TD6) in Sierra de Atapuerca include Ursus sp.,Crocuta crocuta, Mustela palerminea, Lynx sp., Canis mosbachensis and Vulpes praeglacialis. Approximately 80 human remains belonging to Homo antecessor were ...

Even though the Cenozoic has been recognized as a period of important climate change, long-term climatic changes that took place in the continental domain are still questioned. For an area, southern Germany, for which other long-term palaeoclimatic records exist, analysis of oxygen isotope composition of small mammal teeth has been carried out for localities ranging in age from the late Eocene (c.36 Ma) to the middle Miocene (c.10 Ma). Comparison of this long-term continental δ18O record with the marine record reveals comparable trends. The major Cenozoic climatic events are thus recognized in the continental oxygen isotope record.Through comparison with other quantitative palaeoclimatic reconstructions available for the studied area, temperatures in southern Germany are broadly estimated to have fluctuated between 12 °C and 25 °C from late Eocene to early late Miocene. According to the different available chronological frameworks, either a ∼ 2 °C (considering the classical biostratigraphy) or a ∼ 6 °C (considering a revised biostratigraphy) decrease in mean air temperature is estimated for the Eocene/Oligocene boundary.